Radiant barriers are installed in buildings to reduce summer heat gain and winter heat loss, and hence to reduce building heating and cooling energy usage. The potential benefit of attic radiant barriers is primarily in reducing air-conditioning cooling loads in warm or hot climates. Most of the known radiant barriers are composite members consisting of a thin sheet or coating of a highly reflective material, such as aluminum, applied to one or both of opposite face surfaces of a suitable substrate material. The substrate maybe kraft paper, plastic films, cardboard, or the like. Some products are fiber reinforced to increase the durability and/or stiffness. The reflective panel may also be comprised in whole or in part of a plastic, paper, or corrugated sheet of material covered by a reflective material such as aluminum or other metal foil or even a reflective coating such as a metallic paint.
Radiant barriers work by reducing heat transfer by thermal radiation across the air space between the roof deck and the attic floor and may be installed in attics in several configurations. The simplest method of application is to lay the radiant barrier directly on top of existing attic insulation, with the reflective side up. Another way is to attach it near the roof and a still further way is to drape the radiant barrier over the tops of the rafters before the roof deck is applied. Another variation is to attach the radiant barrier directly to the underside of the roof deck.
The following references, directed to reflective insulation panels, rafter vents, radiant barriers and the like reference, are considered to be only of interest: U.S. Patent Publication 2008/0134608 by Snyder published Jun. 12, 2008 Snyder; U.S. Patent Publication 2007/0259155 by Zupon et al. published Nov. 8, 2007; U.S. Pat. No. 7,302,776 by Duncan et al. granted Dec. 4, 2007; U.S. Pat. No. 6,926,785 by Tanzer et al. granted on Aug. 9, 2005; U.S. Pat. No. 6,800,352 by Hejna et al. granted Oct. 5, 2004; U.S. Pat. No. 6,444,286 by MacKenzie granted Sep. 3, 2002; and U.S. Pat. No. 6,346,040 granted on Feb. 12, 2002.
In residential homes typically the roof structure is formed of materials which inherently have minimal thermal insulating and emissivity barrier properties. Therefore, heat transfer through the roof structure from the outdoors to the interior space of for example, a home, particularly during the summer months, is a problem to the home owner. Either the home owner undergoes severe discomfort due to the elevated temperatures inside the house or they must pay a high price for utilities including installation and operation of an air conditioning system. The insulating solar or heat emitting properties of a structural roof have undergone limited improvements. Excess heat transfer is generated on a daily basis at least in the summer months penetrating into the interior of building materials such as sheet rock and insulation and cause unwanted elevated temperatures within the interior living space. Thus under conventional home construction conditions, the air temperature in attics and ceilings can be raised to about 140 degrees F. or higher.